Set variables in Javascript from Excel spreadsheet

I have a Javascript that displays a timer on a screen and when the timer reaches a set value it changes the colour of the backround to 'Red'. I need to be able to dynamically change this variable, based on a set of circumstances. I was wondering is it possible to set the value of the Javascript variable from a cell in Excel. I have provided my code below, clock_limit is the variable I want to be able to set using a cell from an Excel spreadsheet.

JavaScript that is executed on a web page cannot read or write files of any type.

If the Excel file is on the server, you could use a helper language like PHP to read the Excel file and pass the value along to JavaScript. The workflow for this is not that complicated, but you'll need to use a third party library for parsing the Excel file. This can be done with other server side languages (other than PHP) too.

If the Excel file is on the client, you will either need to upload it to the server, or use a client-side language that is able to elevate its privileges (like Flash or Java). The workflow for this is not particularly simple.

JavaScript that is executed on a web page cannot read or write files of any type.

If the Excel file is on the server, you could use a helper language like PHP to read the Excel file and pass the value along to JavaScript. The workflow for this is not that complicated, but you'll need to use a third party library for parsing the Excel file. This can be done with other server side languages (other than PHP) too.

If the Excel file is on the client, you will either need to upload it to the server, or use a client-side language that is able to elevate its privileges (like Flash or Java). The workflow for this is not particularly simple.